The 28 year old was in the Southland for a stopover as he flew from Kansai, Japan, through Inchon, Korea, and then LA on his way to Boston.

Agents became suspicious of Harris, a naturalized US citizen of Chinese descent, when they noticed him wearing what appeared to be ballistic gear, according to court documents.

When asked for his customs declaration, Harris told the officers he had a knife in his bag.

In addition to the smoke grenade, the following items were found in Harris’ checked bag, according to ICE:

three lead-filled, leather-coated billy clubs,

a collapsible baton,

a full-face respirator,

various knives and masks,

a hatchet,

body bags,

a biohazard suit,

handcuffs,

leg irons,

duct tape, batteries, oven mitts, cooking tongs,

and a device to repel dogs.

Federal officials told NBC News they are not under the impression that Harris was a terrorist or was plotting to do anything on the various planes he was flying on. A motive remained unclear late Tuesday.

According to ICE, the smoke grenade still under investigation could cover nearly 40,000 cubic feet with smoke, enough to fill the cabin of a commercial airplane. If the grenade is ignited without sufficient airspace, it’s capable of sparking a fire.

The airline that allowed Harris to begin his journey has not been identified, though a federal official said the Japan-to-Korea flight was not on a U.S. carrier.

Harris' attorney said his client has no criminal history, and is employed in Japan.

If convicted of transporting hazardous material, Harris could face a fine up to $25,000, five years in prison, or both.

He appeared Tuesday in a federal court in Los Angeles for a 2-minute hearing, which was continued until Friday at 10 a.m. Harris remains in custody. No bail has been set.